This invention relates to header of a crop cutting apparatus such as a swather or a combine harvester which includes a flexible cutting knife.
Headers for a crop harvesting machine generally comprises a main longitudinal support member in the form of an elongate tube which extends across substantially the full width of the header frame and defines a main structural member for the header frame. The tube carries a plurality of forwardly and downwardly extending support beams which include a first portion extending downwardly and a second portion attached to a lower end of the first portion and extending forwardly therefrom toward a forward end of the support beams. The cutter bar is attached to the forward end of the support beams and is thus held thereby in a position generally parallel to the main support tube.
Many headers are of a type in which the cutter bar is intended to be in a fixed rigid position relative to the main support tube so that the cutter bar is not intended to flex or float relative to the main structural tube in response to changes in ground contour.
This rigid type of header has the advantage that it allows more accurate control of the position of the fingers or bats of the reel relative to the cutter bar so as to more accurately control the crop as it is swept onto the cutter bar and the table rearwardly of the cutter bar.
In this rigid header type, therefore, the support beams extending forwardly from the main structural tube are substantially rigid and hold the cutter bar in fixed position.
Alternative types of header mount the cutter bar for floating or flexing movement relative to the main structural support tube. This type of header is used to provide an improved action in following the contour of the ground and is advantageous in some circumstances. Thus when cutting crops right at the ground it is desirable that the cutter bar of larger headers, greater than of the order of 20 feet, is somewhat flexible to follow the ground contour. This type of header however has the disadvantage that the flexing or floating of the cutter bar relative to the main support tube causes movement of the cutter bar relative to the bats or fingers of the reel so that it is no longer possible to maintain a close tolerance between the bats or fingers and the cutter bar.
Various manufacturers provide a flexing cutter bar structure for example the Soybean Header manufactured by Case IH under the Model No 820 or 1020.
Another type of header provide a cutter bar which is relatively rigid but can float upwardly and downwardly relative to the main structural support tube of the header. This type of header again is used to allow close floating action of the cutter bar on the ground surface and one example is shown in the xe2x80x9cDial-a-matic Header Height Controlxe2x80x9d available for various Deere and Company combine harvesters. This floating action of a cutter bar however occurs relative to the main structural tube and therefore relative to the reel so that the cutter bar to reel co-operation cannot be optimized.
It is known that rigid headers are conventionally flexibly mounted to the propulsion machine, that is a swather tractor, combine harvester or pull type frame, and the header as one piece can generally follow the ground contour while the cutting knife remains rigid.
It is also known that headers of this type can be controlled so that they rotate around an axis at a centre of the header in response to sensors which detect ground height so as to maintain the sides of the header as close to the ground as possible.
When cutting above the ground, a header of this type with a rigid knife structure is most effective because the rigid knife structure allows maximum cutting speed and thus an improved cutting action.
When cutting on the ground with larger headers, it is known to have a cutter bar which is mounted on the header so that it can flex or float across its width relative to the ground. Examples of such flexible cutter bars are shown in U.S. Pat. No. 4,665,685 (Rupprecht) issued May 19, 1987 and U.S. Pat. No. 4,875,331 (Ostrup) issued Oct. 24, 1989. Both of these arrangements show a cutter bar which is mounted on a skid and thus skids across the ground and flexes across its whole width to accommodate changes in height of the ground. One disadvantage of the conventional flexible cutter bar is that it may in some designs require a significantly reduced cutting speed since the reciprocation of the conventional sickle knife must be reduced in velocity to accommodate the curvature of the cutter blade which can occur when the whole of the cutter blade is flexible. Conventionally a flexible cutter bar of this type can flex as much as a total of five to six inches to accommodate the changes in ground height which occur relative to the fixed part of the header frame which remains fixed and does not change relative to ground height.
A further disadvantage of a flexible cutter bar of this type is that it is necessary to set the reel at a height which accommodates the upward movement of the cutter bar which can occur. The reel fingers therefore must necessarily be spaced a significant distance from the cutter bar to avoid the possibility that the raised cutter bar interferes with the fingers and causes damage to either or both. This increased distance between the fingers of the reel and the cutter bar can cause irregular or improper feed of the crop material over the cutter bar particularly in light crop conditions so that an accumulation of cut crop on the cutter bar can eventually halt further cutting action leaving a part of the crop uncut and thus unharvested.
The disadvantage of the rigid cutter bar design is that rather than floating over a small area like a ridge or gopher mound, the rigid header pushes dirt in front of the sickle knife which impedes cutting and allows dirt to enter the header with the crop.
Up till now, therefore, the rigid header arrangement with its accurate reel finger to cutter bar location is not fully satisfactory as it cannot accurately follow ground contour; and the flexible cutter bar design, which can follow ground contour, is also not fully satisfactory in view of the increased and varying space between the reel fingers and the cutter bar.
In U.S. Pat. No. 4,956,966 (Patterson) issued September 1990 and assigned to the present Assignee is disclosed a header which includes drapers for transporting the crop inwardly from the sides of the header toward the central discharge section. The use of drapers can provide an arrangement which allows the header table to flex although the arrangement shown in the patent and the product manufactured in accordance with the patent provides a rigid header of the type described above. The header of Patterson includes a central link by which the position of the upper end of the header can be pulled toward or released from the supporting vehicle so as to change the angle of the frame of the header about an axis across the width of the header. A skid plate can be provided just behind the cutter bar which can run across the ground so that the change in angle of the header changes the angle of the cutter bar in front of the skid plate.
In U.S. Pat. No. 5,464,371 (Honey) issued November 1995 to Honeybee Manufacturing is disclosed a draper header of a type similar to that disclosed in Patterson.
In U.S. Pat. No. 4,446,683 (Remple) issued May 1984 to Canadian Cooperative Implements is disclosed a header for a swather which includes a central section and two wing sections in which the wing sections can pivot about a forwardly extending axis to allow the outer ends of the wing sections to be raised to a height as much as six feet from the ground. The cutter bar is continuous through the pivot axes so that the cutter bar flexes as the hinging action occurs. The patent led to development of a product manufactured by the above company which utilized the arrangement of the wing sections and the flexible cutter bar. There were a significant number sold but it is not being built any more and the arrangement is no longer commercial. The device supported the center section on the swather tractor but the wing sections were supported upon individual ground wheels mounted at the ends of the wing sections. It is necessary therefore to control the height of the wing sections by actuating movement of the ground wheels and this arrangement therefore did not allow the system to accurately follow the ground contour.
In U.S. Pat. No. 4,409,780 (Beogher) issued October 1983 to Kansas State University is disclosed a header with three independent sections so that two wing sections can be folded rearwardly for transport. However this arrangement does not provide a flexible arrangement which allows the cutter bar as a whole to accurately follow the ground contour.
In U.S. application Ser. No. 09/562,854 filed May 1, 2000 is disclosed an alternative arrangement for a header with a flexible crop cutting knife. This application discloses an arrangement in which the header frame is rigid and supports rigid ends of the cutter bar with a center section of the cutter bar being flexible upwardly and downwardly and the control of inner frame elements of the otherwise rigid header construction.
The assignee of the present application which is Macdon Industries of Winnipeg Manitoba Canada manufactures a header where the feed system uses drapers which can be used on a swather tractor or on a combine harvester using an adapter and this is sold under the designation 962 or 972. This machine provides the basis for the present invention and the present invention uses many of the constructions of this machine. Reference is made therefore to this machine which is well known and readily available to one skilled in this art for the engineering and constructional details which are omitted from the schematic illustrations herein.
It is one object of the present invention to provide an improved header which allows flexible movement of the cutter bar.
According to a first aspect of the invention there is provided a crop harvesting header comprising:
a main frame structure extending across a width of the header for movement in a forward direction generally at right angles to the width across ground including a crop to be harvested;
a mounting assembly for carrying the main frame structure on a propulsion vehicle;
a crop receiving table carried on the main frame structure across the width of the header;
a cutter bar across a front of the table arranged to move over the ground in a cutting action and carrying a cutter knife operable for cutting the crop as the header is moved forwardly across the ground for depositing the crop onto the table;
a skid element extending across the width of the header for engaging the ground so as to receive lifting forces from the ground at whatever points of the skid element contact the ground tending to lift the cutter bar;
a crop transport system on the table for moving the cut crop toward a discharge location of the header;
the main frame structure being divided into a first frame portion and a second separate frame portion with the second connected to the first by a pivot coupling arranged for pivotal movement of the second relative to the first about a pivot axis extending in a plane parallel to the forward direction and intersecting the cutter bar so that, as the second pivots relative to the first, the cutter bar bends in the area adjacent the respective pivot axis to accommodate the pivotal movement;
the pivot coupling of the second frame portion relative to the first frame portion being arranged such that weight from the second frame portion outboard of the pivot coupling tends to rotate the second frame portion about the pivot coupling in a downward direction;
the mounting assembly including a support assembly arranged to provide a total lifting force from the propulsion vehicle acting to support the main frame structure for floating movement relative to the propulsion vehicle such that upward pressure from the ground on the skid element, which is greater than a downward force from a part of the weight of the header unsupported by the lifting force, tends to lift the main frame structure relative to the propulsion vehicle;
the support assembly being arranged such that the total lifting force can be varied so that the total downward force, from that part of the weight of the header which is unsupported by the lifting force, can be varied to change the total pressure of the skid element on the ground;
the support assembly including a first component arranged to provide a first lifting force for the first frame portion;
the support assembly including a second component arranged to provide a second lifting force for the second frame portion;
the support assembly being arranged to provide floating movement for each of the first and second frame portions relative to each other and relative to the propulsion vehicle such that upward pressure from the ground on the skid element, which is greater than a downward force from a part of the weight of the header unsupported by the lifting force, tends to lift each of the first and second frame portions relative to the propulsion vehicle;
the first and second components being arranged such that the first and second lifting forces vary as the total lifting force is varied and such that the lifting force is balanced across the width of the first and second frame portions.
In many cases, as defined hereinafter there is provided a central section mounted on the vehicle and two wing sections, which is in most cases the most practical arrangement providing sufficient flexibility without excessive complication and expense. However the principles of this invention can be applied to alternative constructions can be used which allow a plurality of sections to be carried on a propulsion vehicle and for the weight per unit length of each as applied to the ground to vary as the total weight is varied.
Thus in one example there may also be two additional outer wing portions each pivotally mounted to an outer end of the inner wing potion and each having a respective pivot coupling and linkage which controls the position of the cutter bar as defined herein.
In another construction there may be in effect only two wing portions where each is connected to the other for the pivotal movement defined herein.
In yet another construction there may be only one main portion and in effect a single wing pivoted from it.
The above definition of the invention therefore relates to the interconnection between the two portions without specifying how they are connected to the propulsion vehicle and without specifying whether there are more than one pivotal second portion. Further definitions of the invention more particularly directed to the three portions defined by the center portion and two wings are also included herein.
In most but not necessarily all cases, the header will include a conventional reel. If included, the fact that the reel is mounted in conventional manner so that its position is in a specified location relative to the main frame of each portion ensures that it is in a specific relation to the cutter bar or each portion. Thus the reel can be mounted at one end in on one portion and at the other end on the other portion which locates those ends relative to the cutter bar at the respective ends and avoids the situation where the cutter bar position is indeterminate relative to the reel. While there is still movement between the reel and the cutter bar, thus changing the spacing between the fingers and the cutter bar, this will be much less than for a conventional flexing cutter bar where the cutter bar can flex relative to the frame and thus relative to the reel. In the preferred arrangement where the frame includes a center portion and two wing portions, the reel may be located on two end arms each supported on the outer ends of the wing portions and also on a central arm mid way across the center portion, since this provides three points where the inter-relation between the reel and the cutter bar is specified, even though the positions in between may vary. In another arrangement, the reel may be mounted on four arms, two at each end and two at the pivot points, which provides improved control over the reel to cutter bar distance but increases the complexity of the reel.
The reel is preferably of the type mounted on conventional arms pivoted to the frame which allow adjustment of the height of the reel relative to the cutter bar. Suitable engineering arrangements for providing the necessary flexing and expansion of the sections of the reel to accommodate the flexing action of the header are well known to one skilled in the art. In addition, fixed reels attached at fixed location to end sheets of the header frame could also be used and the invention is not limited in this regard.
The term xe2x80x9cspringxe2x80x9d as used in this document is not intended to be limited to a particularly type of element which provides a spring or biasing force but merely defies any element which will allow resilient movement of one component relative to another. This can be provided by a mechanical flexing link such as a coil or tension spring or can be provided by fluid such as air or hydraulic cylinders and the term is also intended to include the suitable mechanical couplings of those links to the required elements. Hydraulic cylinders with suitable accumulators for taking up and releasing fluid to the cylinders are effective in this regard.
The above definition refers to xe2x80x9cbendingxe2x80x9d of the cutter bar. This bending movement can be obtained by providing a specific hinge between two parts of the bar or by providing a cutter bar which can flex sufficiently to accommodate the required bending without the necessity for an actual hinge defining a specific pivot axis.
The term xe2x80x9cskid elementxe2x80x9d used in the above definition is not intended to be limited to a particular component of the header and may be provided by any element which physically engages the ground as the cutter bar and knife elements carried thereby proceed across the ground. Thus the skid element may be provided by the cutter bar itself or by an additional component behind the cutter bar. In addition, closely spaced rollers or other elements which roll over the ground and thus reduce friction may be used provided that the lifting force is spread evenly across the cutter bar to provide the floating action to which this invention is directed, although this is not generally necessary and not conventionally used.
The mounting assembly may be an adapter frame arranged for connection of the header to an existing feeder house of a combine harvester. However such an adapter is not essential and the mounting assembly may be constituted by simply connecting elements which directly couple the header to the combine harvester.
In one preferred arrangement, the linkage is arranged such that adjustment of the mounting assembly to effect variation of the total downward force automatically provides adjustment of the linkage such that the downward force of the second frame portion varies separately as the total downward force is varied.
Preferably the linkage is arranged to provide a spring coupling to the first frame portion for floating movement of the outboard weight of the second frame portion to the first frame portion. In this arrangement, the linkage is preferably a non-spring linkage and the spring coupling is provided by a connection to said at least one spring of the mounting assembly such that the floating movement is provided at least partly by said at least one spring.
Where the adjustment of the linkage is effected automatically, this can conveniently be done by the linkage including a pivotal balance beam to which is applied as three balanced forces a) said lifting force from the propulsion vehicle, b) at least part of the weight from the first frame portion and said weight applied to the first frame portion from the second frame portion at the pivot coupling and c) said outboard weight of the second frame portion. In this arrangement, the balance beam is preferably located at the first frame portion, the balance beam preferably extends in the forward direction, the mounting assembly preferably includes a lift arm extending in the forward direction parallel to and underneath the balance beam and the lift arm is preferably arranged to apply to the balance beam force a) at a position forwardly of force b) which is applied forwardly of force c). Also preferably the linkage includes a tension link extending from the second frame portion to the first frame portion at a position above the pivot coupling and arranged to connect to the balance beam to apply said force c) thereto in an upward direction, where the tension link includes a bell crank on the first frame portion above the balance beam.
Preferably the bell crank is adjustable to balance the forces b) and c) to hold the cutter bar straight when the upward pressure from the ground is constant along the cutter bar.
As is conventional, preferably the mounting assembly includes two lift arms each carried on a respective spring and spaced apart across the first portion such that the first portion can float upwardly and can twist about an axis in the forward direction, with each spring carrying a part of the weight of the header.
Preferably, where each of the portions includes a conventional horizontal main frame beam, the pivot coupling between the second frame portion and the first frame portion is arranged below the main beams.
Preferably the pivotal movement between the second frame portion and the first frame portion is less than a total of 6 degrees and more preferably less than 4 degrees, which angles are sufficient to provide the flexibility of the cutter bar which is required without providing any additional movement for transport or the like. This limited movement provides a simple construction and may avoid the necessity for a hinge in the cutter bar while allowing a single high speed knife to move along the cutter bar through the hinge or flex section.
In most cases the header is unsupported by ground wheels such that all lifting forces from the ground are communicated through said skid element.
In accordance with an important preferred aspect of the invention there is provided a bottom stop member arranged such that downward floating movement of the header is halted at a bottom position when the header is lifted to a raised position in which the skid element is spaced from the ground so that there is no lifting force from the ground and wherein there is provided a balance mechanism to balance the second portion in aligned position so the cutter bar is straight when the header is in the raised position.
Where the linkage includes a pivotal balance beam as set forth above, the balance mechanism may be arranged to apply balance forces from the bottom stop member to the balance beam.
In accordance with an alternative arrangement, the interconnecting linkage which transfers the outboard weight of the second frame portion to the first frame portion may include its own spring separate from the spring of the mounting assembly, the spring being arranged such that a spring force provided thereby is adjustable in response to the variation of the lifting force provided by the mounting assembly such that the downward force of the second frame portion varies separately as the total downward force is varied.
In accordance with another alternative arrangement, the interconnecting linkage which transfers the outboard weight of the second frame portion to the first frame portion may include an actively driven coupling for adjusting the height of the outboard end of the second portion and there is provided a sensor responsive to changes in lifting force from the ground at points along the cutter bar for controlling the actively driven coupling. This arrangement thus provides a construction which relies on sensors to maintain the required balance of the system rather than using the forces from the ground in the balancing action as used in the balance beam system defined above. However this arrangement, while more complex and more reliant on sensors, can also be used and falls within the scope of this invention.
In accordance with second aspect of the invention there is provided a crop harvesting header comprising:
a main frame structure extending across a width of the header for movement in a forward direction generally at right angles to the width across ground including a crop to be harvested;
a mounting assembly for carrying the main frame structure on a propulsion vehicle;
a crop receiving table carried on the main frame structure across the width of the header;
a cutter bar across a front of the table arranged to move over the ground in a cutting action and carrying a cutter knife operable for cutting the crop as the header is moved forwardly across the ground for depositing the crop onto the table;
a skid element extending across the width of the header for engaging the ground so as to receive lifting forces from the ground at whatever points of the skid element contact the ground tending to lift the cutter bar;
a crop transport system on the table for moving the cut crop toward a discharge location of the header;
the main frame structure being divided into a first frame portion and a second separate frame portion with the second connected to the first by a pivot coupling arranged for pivotal movement of the second relative to the first about a pivot axis extending in a plane parallel to the forward direction and intersecting the cutter bar so that, as the second pivots relative to the first, the cutter bar bends in the area adjacent the respective pivot axis to accommodate the pivotal movement;
the pivot coupling of the second frame portion relative to the first frame portion being arranged such that weight from the second frame portion outboard of the pivot coupling tends to rotate the second frame portion about the pivot coupling in a downward direction;
the mounting assembly including a support assembly arranged to provide a total lifting force from the propulsion vehicle acting to support the main frame structure for floating movement relative to the propulsion vehicle;
the support assembly being arranged such that the lifting force can be varied;
the support assembly including a first component arranged to provide a first lifting force for the first frame portion;
the support assembly including a second component arranged to provide a second lifting force for the second frame portion;
wherein the support assembly includes a balancing connection between the first and second components which is arranged such that adjustment of the support assembly to effect variation of the total lifting force automatically balances the first and second lifting forces proportionally and such that the lifting force is balanced across the width of the first and second frame portions.
Preferably the balancing connection comprises a pivotal balance beam to which is applied as three balanced forces a) said total lifting force from the propulsion vehicle, b) said first lifting force and c) said second lifting force.
While this definition refers to the use of two portions, it will again be appreciated that more than two portions and preferably the three portions arranged in center and two wing format can be used.
According to a third aspect of the invention there is provided a crop harvesting header comprising:
a main frame structure extending across a width of the header for movement in a forward direction generally at right angles to the width across ground including a crop to be harvested;
a mounting assembly for carrying the main frame structure on a propulsion vehicle;
a crop receiving table carried on the main frame structure across the width of the header;
a cutter bar across a front of the table arranged to move over the ground in a cutting action and carrying a cutter knife operable for cutting the crop as the header is moved forwardly across the ground for depositing the crop onto the table;
a skid element extending across the width of the header for engaging the ground so as to receive lifting forces from the ground at whatever points of the skid element contact the ground tending to lift the cutter bar;
a crop transport system on the table for moving the cut crop toward a discharge location of the header;
the main frame structure being divided into a first frame portion and a second separate frame portion with the second connected to the first by a pivot coupling arranged for pivotal movement of the second relative to the first about a pivot axis extending in a plane parallel to the forward direction and intersecting the cutter bar so that, as the second pivots relative to the first, the cutter bar bends in the area adjacent the respective pivot axis to accommodate the pivotal movement;
the pivot coupling of the second frame portion relative to the first frame portion being arranged such that weight from the second frame portion outboard of the pivot coupling tends to rotate the second frame portion about the pivot coupling in a downward direction;
the mounting assembly including at least a support assembly arranged to provide a lifting force from the propulsion vehicle acting to support the main frame structure for floating movement relative to the propulsion vehicle;
the support assembly being arranged such that the lifting force can be varied;
the support assembly including a first component arranged to provide a first lifting force for the first frame portion;
the support assembly including a second component arranged to provide a second lifting force for the second frame portion;
the support assembly being arranged to provide floating movement for each of the first and second frame portions relative to each other and relative to the propulsion vehicle;
wherein there is provided a bottom stop member arranged such that downward floating movement of the header is halted at a bottom position when the header is lifted to a raised position in which the skid element is spaced from the ground;
and wherein there is provided a balance mechanism to balance the first and second portions in aligned position so the cutter bar is straight when the header is in the raised position.
Again this definition refers to the use of two portions, but it will again be appreciated that more than two portions and preferably the three portions arranged in center and two wing format can be used.